A medical system includes: an endoscope including an insertion portion that can be inserted into a body cavity of a subject, and an image pickup section provided at a distal end portion of the insertion portion an exclusion section capable of, when the insertion portion is inserted into the body cavity of the subject, excluding a tissue existing around the distal end portion a computing section that obtains luminance information relating to a luminance of an image picked up by the image pickup section, and determines whether or not the obtained luminance information meets a predetermined condition a drive section that performs or stops an operation to drive the exclusion section based on a determination result of the computing section.